Preparation of coal slurries for transportation



Patented Oct- 3, 1944- PREPARATION OF GOAL SLURRIES FOR I TRANSPORTATION Elliott B. McConnell, Shaker Heights, and Elna:

Ohio,

Standard Oil Company,

Titration of Ohio No Drawing.

assignoro to The Ohio, a cor- Application September 24, 1940, Serial No. 358,152

Claims. (Cl. 302-86) This invention relates to the preparation of coal slurrles for transportation through unprotected ferrous metal piping, and has particular reference to preparing the coal slurry for such transportation so as to preclude corrosion of the piping during such transportation.

In Patent No. 2,128,913 to Robert E. Burk,

there is set forth the transporting of coal in slurry form through pipe lines. Under some con-' ditions there is a tendency for coal slurries to cause corrosion of the customary steel pipes such as are used in pipe line construction, and the corrosion may be such as to be of an undesirable character and rate from an economic standpoint. In accordance with the present invention, action of this character may be obviated, and coal slurries may be transported by pipe lines without corrosion more serious than may be encountered inch and gas lines.

' To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described, and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative however, of but a few of the various ways in which the principle of the invention may be employed.

The coal, usually bituminous, but in some instances anthracite, is suitably ground and made up into suspension in water or aqueous liquid, for instance, the fineness of grinding depending somewhat upon the coal and the distance of pumping, etc., and a stabilizing or anti-settling agent may be included, as for example a soap of oleic, stearic, lauric, palmitic, etc., acid with a base, as ethanolamine, sodium, potassium, etc. The slurry is now subjected to de -oxygenation, and then is put into the pipe line and transported to its point of disposal, suitable pumping units forwarding the liquid. The de-oxygenating may be carried out by allowing the coal suspension to pre age or auto-digest with the coal in "contact.

with the water under conditions excluding uptake of more air, as in a suitably closed treating chamber, the contained oxygen being allowed to thus under controlled conditions combine with the coal, or at least go into such a condition that it is no longer free to preferentially attack the metal surfaces of the pipe line. Desirably, agi-- tation is applied during the auto-digestion. The temperature may be any ordinary range, or slightly elevated. Generally, an aging or digesting treatment of one to two hours reduces the it is innocuous to the pipe line. A convenient arrangement in conjunction with grinding and slurry-forming means is a suitably large cantainer to receive the slurry, and preferably being provided with agitating means, which in the case of an elongated treating chamber may serve also to forward the material at such rate as is desired. The digesting chamber should-be closed so as to exclude entrance of additional air. From the digesting chamber, a connection leads to the We therefore particularly point out and distinctly claim as our invention:

1. The method cf'preparing an aqueous suspension of coal for transportation by pumping through ferrous metal piping to substantially preclude corrodingthe piping, which comprises forming an aqueous suspension of finely-divided coal as a pumpable slurry containing oxygen introduced during such slurry formation, and autodigesting the slurry at ordinary temperatures for a suflicient time to eflfect substantially complete elimination of the iron-corrosive oxygen in the, slurry prior to pumping the slurry through the ferrous metal piping, whereby the slurry may then be pumped through said ferrous metal piping without corroding the same.

2. The method of preparing an aqueous suspension of coal for transportation by pumping through ferrous metal piping to substantially preclude corroding the piping, which comprises forming an aqueous suspension of finely-divided coal, as a pumpable slurry containing oxygen introduced during such slurry formation, and substantially deoicvgenating the slurry by agitating it in the substantial absence of added oxygen for a period of about one to about two hours prior topumping the slurry through ferrous metal piping, whereby the slurry may then be pumped through said ferrous metal piping without corrodingthe same.

free oxygen content of the slurry to a point where u 3. The method of preparing an aqueous suspension of coal for transportation by pumping through ferrous metal piping to substantially preclude corroding the piping, which comprises form- 2, ing an a'queous suspension of finely-divided coal as a pumpable slurry containing oxygen introduced during such slurry formation, and subjecting the slurry to an autodigestion step in a closed space for a predetermined time to effect combination of the oxygen contained in the slurry with the coal prior to pumping the slurry through ferrous metal piping, whereby the slurry may then be pumped through said ferrous metal piping without corroding the same.

4. The method of preparing an aqueous suspension of coal for transportation by pumping through ferrous metal pipin to substantially preclude corroding the piping, which comprises forming a stable suspension of finely-divided coal with water as a pumpable slurry containing oxygen introduced during such slurry formation, and subjecting the slurry to agitation at ordinary temperatures in the substantial absence of added oxygen for a period of about one hour to about two hours to effect substantially complete inactivation of the oxygen contained in the slurry prior to pumping the slurry through ferrous metal piping, whereby the slurry may then be pumped through said ferrous metal piping without corroding the same.

5. The method of preparing an aqueous suspension of coal for long-distance transportation by pumping through ferrous metal piping to substantially preclude corroding the piping, which comprises forming the aqueous suspension of finely-divided coal as a pumpable slurry containing corrosion-inducing oxygen introduced during i such slurry formation, autodigesting the slurry in the substantial absence of added oxygen for a predetermined period to inactivate the said contained oxygen by combination with the coal, and agitating the slurry during said autodigestion period to facilitate the inactivation of said contained oxygen preparatory to conducting the slurry through unprotected ferrous metal piping,

whereby the'slurry may be transported through such piping without corroding the same.

ELLIO'I'I B. McCONNEIL. EINAR KROPP. 

